Controle da lagarta do cartucho (Spodoptera frugiperda) via ingestão de samambaia (Pteridium aquilinum) / Fall armyworm control (Spodoptera frugiperda) through ingestion of bracken (Pteridium aquilinum)

RESUMO

Considerando a ação tóxica da samambaia de P. aquilinum para vertebrados, verificou-se sua atividade inseticida e uso potencial no controle de pragas agrícolas, testando seus efeitos sobre S. frugiperda. Extrato etanólico bruto foi feito com a parte aérea de P. aquilinum, sendo incorporado à dieta artificial (controle ou livre de extrato, 1% e 2%) com 50 repetições (lagartas). Houve mortalidade significativa (34% e 86%) nas concentrações de 1% e 2%, respectivamente, em comparação ao controle (10%). Nos tratamentos a 1% (20,03 dias) e 2% (20,42 dias), observou-se prolongamento do estágio larval (13,51 dias) no tratamento controle. Nos dias 3, 6, 9 e 12 após o tratamento, houve redução de peso, e o tratamento com 2% resultou em larvas 73% mais leves que o controle no dia 12. As pupas do tratamento a 2% foram mais leves que as demais. Em conclusão, 1% e 2% do extrato etanólico de P. aquilinum prolongaram o ciclo larval, diminuiu o peso das larvas e das pupas e, na concentração de 2%, causaram mortalidade efetiva de S. frugiperda.

ABSTRACT

Considering the toxic action of P. aquilinum bracken for vertebrates, its insecticidal activity and potential use in agricultural pest control was verified, testing its effects on S. frugiperda. Crude ethanolic extract was made with the aerial part of P. aquilinum, being incorporated into artificial diet (control or extract-free, 1% and 2%) with 50 replicates (caterpillars). There was significant mortality (34% and 86%) at concentrations of 1% and 2%, respectively, compared to control (10%). In treatments at 1% (20.03 days) and 2% (20.42 days), larval stage prolongation (13.51 days) was observed in the control treatment. On the 3rd, 6th, 9th and 12th days after treatment, there was weight reduction, and the 2% treatment resulted in larvae 73% lighter than the control did at day 12. The pupae of the 2%treatment were lighter than the others. In conclusion, 1% and 2% of P. aquilinum ethanolic extract extended the larval cycle, decreased the larvae’s and pupae’s weight, and, at a concentration of 2%, caused effective mortality of S. frugiperda.